Interfacial Engineering and Hydrophilic/Hydrophobic Coatings in Solar Evaporators: Strategies for Balancing Evaporation and Condensation–A Comprehensive Review

Solar-driven steam generation (SSG) is an efficient process for converting solar energy into thermal energy, demonstrating significant potential for industrial use. Recent progress in interfacial engineering, particularly through innovations in photothermal layer design and condenser optimization, has enabled remarkable solar-thermal conversion efficiencies at the air/liquid interface. This review systematically examines interfacial engineering strategies for high-performance evaporators, emphasizing the critical role of hydrophilic/hydrophobic coatings in achieving sustainable water production. Furthermore, it evaluates condensing structures, comprehensively classifying condensers and their influence on freshwater yield. By analyzing key physical factors, including phase-change dynamics, vapor-liquid equilibrium, and enthalpy reduction strategies for photothermal materials (PTMs), as well as the harnessing of ambient energy for enhanced evaporation, this review offers a framework to elucidate the mechanisms of hydrophilic/hydrophobic coatings and identify potential breakthroughs under optimized conditions. Finally, we discuss the prospective applications of SSG systems with advanced evaporators and condensers, alongside the prevailing challenges in scalability and practical implementation.